PP to parallel

merlin el mago · 27th December 2010, 10:32 AM

Please need help, how can do to convert this PP schematic in parallel?

markusA · 27th December 2010, 10:56 AM

Please be a little more specific about what you want?
What do you want to achieve?
What is the purpose?

Vinylsavor · 27th December 2010, 10:57 AM

Hi!

What exactly do you want to achieve? The circuit you've shown is not PP and what do you mean by 'parallel' ?

Thomas

revintage · 27th December 2010, 11:13 AM

I am sure merlin PP refers to that this circuit is called "Shunt Regulated Push Pull". To parallell the two triode-halves to get a conventional CC-stage is no big deal.

merlin el mago · 27th December 2010, 11:38 AM

@ markusA & Vinylsavor
I want to convert the push pull in two triode-halves paralleled with the same valve.

@revintage
Isn't any advantatge to convert the push pull in parallel triode? could you elaborate?

Vinylsavor · 27th December 2010, 12:44 PM

Hi,

Try this:

connect both systems in parallel, use half the cathode resistor value which is in now and double the cathode bypass cap. Connect the output coupling cap to the anodes and a plate resistor 5k/10W from anodes to B+.

Alternatively you can try just single systems: Disconnect the upper system in the SRPP stack, or better ground all unused elements. Leave the cathode R and C and use a 10k plate load resistor.

Best regards

Thomas

revintage · 12:48 PM

Try if you like SE by moving the output cap to below the upper 330ohm. This way the lower triode will be loaded by, in the ballpark of, 20k. This if we assume Ri being just below 10k at this low Ia.

About parallelled 6922 halves I have no idea if it sounds good, haven´t tried. But you have the answer about how to do in Thomas post above. (Our posts crossed)

Vinylsavor · 27th December 2010, 12:47 PM

Hi,

I forgot to add: you should then also change the bias voltage of the heater. As a first try you can simply reference the heater to ground. Or change the voltage divider which elevates the heater to values which will bring it ti about +25V.

Thomas

Vinylsavor · 27th December 2010, 12:49 PM

I couldn't make out the B+ voltage in the schematic, it is difficult to read. For my suggested mod it should be 180...

Thomas

merlin el mago · 27th December 2010, 01:31 PM

Sorry I forgot to told you that the heater now isn't shunt type, each tube has is own heater. Voltage B+ before 4k7 is 180V. Could you draw & post an schematic with changes & values to do?

27th December 2010, 10:32 AM	#1
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Catalonia new Europe state	PP to parallel Please need help, how can do to convert this PP schematic in parallel?

27th December 2010, 12:46 PM	#7
revintage diyAudio Member Join Date: May 2007	Try if you like SE by moving the output cap to below the upper 330ohm. This way the lower triode will be loaded by, in the ballpark of, 20k. This if we assume Ri being just below 10k at this low Ia. About parallelled 6922 halves I have no idea if it sounds good, haven´t tried. But you have the answer about how to do in Thomas post above. (Our posts crossed) Last edited by revintage; 27th December 2010 at 12:48 PM.

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27th December 2010, 10:56 AM	#2
markusA diyAudio Member Join Date: Dec 2009 Blog Entries: 7	Please be a little more specific about what you want? What do you want to achieve? What is the purpose?

27th December 2010, 10:57 AM	#3
Vinylsavor diyAudio Member Join Date: Feb 2002 Location: Lindau	Hi! What exactly do you want to achieve? The circuit you've shown is not PP and what do you mean by 'parallel' ? Thomas

27th December 2010, 11:13 AM	#4
revintage diyAudio Member Join Date: May 2007	I am sure merlin PP refers to that this circuit is called "Shunt Regulated Push Pull". To parallell the two triode-halves to get a conventional CC-stage is no big deal.

27th December 2010, 11:38 AM	#5
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Catalonia new Europe state	@ markusA & Vinylsavor I want to convert the push pull in two triode-halves paralleled with the same valve. @revintage Isn't any advantatge to convert the push pull in parallel triode? could you elaborate?

27th December 2010, 12:44 PM	#6
Vinylsavor diyAudio Member Join Date: Feb 2002 Location: Lindau	Hi, Try this: connect both systems in parallel, use half the cathode resistor value which is in now and double the cathode bypass cap. Connect the output coupling cap to the anodes and a plate resistor 5k/10W from anodes to B+. Alternatively you can try just single systems: Disconnect the upper system in the SRPP stack, or better ground all unused elements. Leave the cathode R and C and use a 10k plate load resistor. Best regards Thomas

27th December 2010, 12:47 PM	#8
Vinylsavor diyAudio Member Join Date: Feb 2002 Location: Lindau	Hi, I forgot to add: you should then also change the bias voltage of the heater. As a first try you can simply reference the heater to ground. Or change the voltage divider which elevates the heater to values which will bring it ti about +25V. Thomas

27th December 2010, 12:49 PM	#9
Vinylsavor diyAudio Member Join Date: Feb 2002 Location: Lindau	I couldn't make out the B+ voltage in the schematic, it is difficult to read. For my suggested mod it should be 180... Thomas

27th December 2010, 01:31 PM	#10
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Catalonia new Europe state	Sorry I forgot to told you that the heater now isn't shunt type, each tube has is own heater. Voltage B+ before 4k7 is 180V. Could you draw & post an schematic with changes & values to do?